Composition for surgical and medical preparations



Patented Oct. 2, 1945 COMPOSITION FOR SURGICAL AND MEDICAL PREPARATIONSCarl W. Patton, Palisades Park, N. J assignor to Carbide and CarbonChemicals Corporation,'a corporation of New York No Drawing. ApplicationJuly 12, 1941, Serial No. 402,236

1 Claim.

This invention relates to molded surgical and medical supports, and hasfor its objects the provision of an improved cast material which islight in weight, transparent, convenient to apply, non-flammable, andresistant to water, acids, alkalies, alcohol and aliphatic hydrocarbonliquids. By means of my invention direct support can be provided forinjured limbs, or movement of an injured body member can be restraineduntil the injured member has healed or improved in strength to such anextent that its support or restraint is no longer required.

The present practice oi; supporting fractured, sprained orotherwiseinjured members of the body involves, besides rigid splints,the use of one of two different types of cast materials, as classifiedwith respect to the manner in which these materials assume a rigid statefrom a moldable state. One type of cast material, an example .of whichis plaster of Paris, consists of a material which is a powder in itsmolding state, but which is capable of forming a dense, rigid,supporting structure upon being hydrated. The other type of castmaterial, an example of which is a fabric bandage impregnated with'asolution of cellulose nitrate, consists of a material which issuificiently flexible when wet with solvent to permit its being wrappedabout the injured member, but which is capable of forming a supportingcast when the solvent is evaporated.

Cast materials in current use have certain serious disadvantages whichare not encountered with the compositions which constitute my,invention. The materials belonging to the class which depend for theiraction upon hydration yield casts which are bulky and heavy, andwhichare somewhat attacked by water and acids. Furthermore, these casts areso dense that X-ray pictures of body members enclosed in them canusually be taken only by high voltage technique, and such pictures areless satisfactory than those obtained with low voltage X-rays. Thematerials belonging to the class which depend for their action uponsolvent evaporation are objectionable because of the highly inflammablecharacter of the solvents and dissolved substances, and because of theodor of the solvents employed. Both classes of materials areinconvenient to apply; both require relatively long periods of time forsetting to a rigid state; and neither permits visual examination of theinjured member enclosed by it.

The material of this invention is not a member of either of theforegoing classes, but depends for its operation upon its novelthermoplastic properties. It has the property of assuming a moldableplastic state at temperatures above room temperatures, but not so highas to cause injury to the patient, and yet it is relatively strong andrigid at room temperatures. My invention comprises a composition of aresinous base material to which a suitable plasticizing material hasbeen added, as will be more iully described herein.

The class of materials embraced by this invention has proved to besuperior to the cast materials now in use, and yields supporting castswhich are not attacked by any of the substances normally encountered inthe use of cast materials. For example, the cast material or thisinvention exhibits great resistance to water,

acids, alkalies, alcohol and aliphatic hydrocarbon liquids. In addition,X-ray pictures of body members enclosed in the new plastic compositionsmay be taken with low voltage X-rays, thus assuring a picture of greaterclarity and detail. Other advantages include the ease with which my castmaterials can be applied, the rapidity with which they become rigid, thecleanliness of their application, involving. as it does, no liquidsetting agents, the transparency of the resulting casts which permitsvisual examination of the injured member while supported within thecast, the non-flammable character of the cast materials, the absence ofodors or fumes both in application and in use, the marked reduction inbulk and weight of the casts, and the provision which can be made forventilation by perforation of the material.

I. have discovered that desirable thermoplastic properties can beimparted to a conjoint polymer or a vinyl ester or an aliphatic acid anda vinyl halide by incorporating certain plasticizing substances with theresin. I preier to use a resinous base material which is a conjointpolymer composed of 5% to 30% or vinyl acetate and to of vinyl chloridein the molecular weight range of 5,000 to 20,000, the average molecularweight being 7,000 to 12,000. The molecular weights are determined fromthe specific viscosity of dilute solutions of the resin according toStaudingers method;

A considerable number of compatibl plasticizing materials may be used toyield the de sired thermoplastic properties when incorporated inrelatively small amounts with this base material. Among these substancesare the halogensubstituted hydrocarbons, such as iodoiorm andchlorinated diphenyl; alicyclic ketones, such as camphor and pyronones,as illustrated by dediphenyl phthalate, and trl(paratertiarybuty1-phenyl) phosphate. f Plasticizing materials having melting oints in therangeirom 40 to 125 C.

are particularly effective for my compositions. I prefer to employplasticizlng materials of the class comprising the aryl esters ofpolybasic-acids,

, particularly phosphoric acid, for-the reason that these substanceshave no objectionable odor and their use involves no fire hazard. Qtherplasti cizers which may be used are included inthe following llst:-- a

Cyclohexyl p-t oluene sulionamide Ethyl o-toluene sulfonamide Ethylp-toluene sulfonamide Chlorinated diphenyls Diglycol sebacate I Ethylo-benzoyl 'benzoate Diphenyl mono(o-chlorphenyl) phosphate Di(triglycolchlorhydrin) phthalate Di(butoxyethyl) phthalate Tricresyl phosphateDiphenyl butyl ketone Diphenyl mono(tertiarybutylphenyl) phate Diphenylmono(o-xenyl) phosphate Xylyl heptadecyl ketone The plasticizingmaterials which I havedescribed materially lower the softening point ofthe vinyl resins described and permit the resinous base material to bereadily molded to any desired form. Advantageous properties of lowmelting point and high strength and toughness of the plasticcompositions can often be secured by using mixed plasticizing agents.Mixtures of triphenyl phosphate and tri(paratertiarybutylphenyl)phosphate are particularly useful in this respect. The addition ofliquid plasticizers, such as triethylene glycol di-2-ethyi butyrate, isuseful to avoidany embrittlement of the compositions caused by certainsolid plasticizing agents. The amount of plasticizer to be employed willvary depending on the particular plasticizer used, but, in general, fromabout to about 25% of plasticizer-by weight of the composition isnecessary to secure the thermoplastic'properties desired.

The compositions described in the following examples will serve toillustrate the formation and use of the cast materials of thisinvention: Example 1.-A composition containing 84.5 parts by weight of aconjoint polymer resin analyzing 10% to vinyl acetate and 85% to 90%vinyl chloride and having an average molecular weight of 8,000 to12,000, together with 12.5 parts of triphenyl phosphate and 3.0 parts oftriethylene glycol di-Z-ethyl butyrate, possessed good thermoplasticproperties. The composition was cast into sheets about a: of an inch.thick by evaporation from an acetone solution. The sheets exhibited aglossy appearance and were so transparent that it was possible to readstandard newsprint through them from a distance of approximately eightfeet. Ventilation holes about 1; inch in diameter on inch centers werereadily drilled through the sheets, and there were no indications oftearing around these holes during the molding operation. The

phos- 'sheets were readily moldable on very short radii at temperaturescomfortably endurable to the human body. Upon cooling, the sheets:became hard, rigid, and tough and did not soiten jflt 115 F., a maximumatmospheric temperature.

A second batch-ref the same composition was ar mixed and calendered intothin films, onto cloth and into thicker sheets. These forms may be usedas bandages as hereafter described.

Using this techniqueit was found desirable to improve the workingproperties of the composition by incorporating minor amounts of arelease material, such as carnaubawax; a lubrieating material, such ascalcium stearate; and a' stabilizing material, such as calciumhydroxide.

Example 2.A second composition contained 80.7 parts by weight of aconjoint polymer resin analyzing 10% to 15% vinyl acetate and 85% to 90%vinyl chloride and having an average molecular weight of 8,000 to12.000; together with 0.8 part of a heat stabilizer composed of amixture of dibutyl tin maleate and dibutyl tin dilaurate in equalproportions, 1.0 part of castor oil, 05 part of stearic acid, 5.0 partsof triphenyl phosphate and 12 parts of tri( paratertiarybu tylphenyl)phosphate. This composition was more pliable at temperatures rangingfrom the maximum atmospheric to those endurable by the hum-an body thanthe composition of Example 1, besides being somewhat more workable whenthe calender forming process was used to form sheets. With theseexceptions the physical properties were substantially identical withthose of the composition of Example 1.

Example 3.A third composition contained 81.7 parts by weight of aconjoint polymer resin analyzing 10% to 15% vinyl acetate and 85% to 90%vinyl chloride and having an average molecular weight of 8,000 to12,000, together with 0.8 part of a heat stabilizer consisting of amixture of dibutyl tin maleate and dibutyl tin dilaur-ate in equalproportions, 1.0 part of castor oil, 0.5 part of phenyl salicylate, alight stabilizer, 10.0 parts of triphenyl phosphate and 6.0 parts oftri(paratertiarybutylphenyl) phosphate. This composition possessedsubstantially the same physical properties as the composition of Example2 with the added economy resulting from the replacement of part of thetri(paratertiarybutylphenyl) phosphate content by tri henyl phosphate.

Thermoplastic cast materials can be used in the form of splints, sheets,strips, or fabric impregnated bandages. For example, splints have beenmade of sheets 1; inch thick and softened to a readily moldable state byimmersion in hot water, cooled to a temperature which would not causethe patient discomfort, and then molded by hand manipulation about theregion where support was required. Any excess material remaining afterfitting can be easily cut away, and the resulting splint secured firmlyin place by binding it with surgical adhesive tape or otherwise. Thematerial also has been used in strip form having, for example, thedimensions 2 inches by 0.010 inch, and in cloth-backed form in which thematerial was calendered or otherwisesecured in a thin layer on a clothbandage. When strips and coated bandages are used, a small blast of aassure 3 surfaces which are not tacky and do not cause the strips toadhere prematur'ely.- When the strip is heated the adhesive ma'terialmelts and penetrates the resin sulilciently to bond successive striplayers securely and thus to prevent lateral slipping and displacementbetween the layers.

The expression supporting casting materia as used herein refers to amaterial-which is formed or forma-ble into casts which may be used, forinstance, by being applied to a person's body to support an injuredmember until it is healed.

Many diflerent embodiments of this cast material and variations in itsuse, other than as described in the foregoing examples are possiblewithout departins from the scope oi the invention.

I claim:

Supporting cast material characterized by Q0 hardness. strensth,rigidity and toughness at room temperatures and at body temperaturescombined vinyl chloride content of approxil' mately 10% to 05% by weizhtand a plasticizing material which is a mixture or triphenyl phosphateand tri(paratertlarybutylphenyl)l phosphate', said composition beinssubstantially free from volatile solvent and containing suliicient llplasticizer within the ranse of about 10% to 25% by weight ofplasticiser based on the weight of the composition to live the materialthe aforesaid characteristics.

CARL W. PA'I'ION.

